1. Field
The present general inventive concept generally relates to providing a display apparatus and a method of controlling the same, and more particularly, to providing a display apparatus using an organic light-emitting diode (OLED) and a method of controlling the same.
2. Description of the Related Art
In general, a display apparatus divides one frame into a plurality of sub fields and emits light in pixels of each of the sub fields for different times to represent a gray scale value of one frame. For example, if the display apparatus is to represent the frame as 256 gray scales, the display apparatus divides one frame into first through eighth sub fields and emits light in the eight sub fields by weights of 1, 2, 4, 8, 16, 32, 64, and 128 to represent 256 gray scales. However, according to this method, a false contour occurs due to an emission time difference.
FIGS. 1 through 2B are views illustrating problems of an existing display apparatus.
Referring to FIG. 1, pixels a, b, c, d, and e have 127 gray scales, and pixels f, g, h, i, and j have 128 gray scales. In other words, weight values 1, 2, 4, 8, 16, 32, and 64 are respectively given to first through seventh sub fields SF1 through SF7 so that the pixels a, b, c, d, and e have gray scale values. Also, weight value 128 is given to an eighth sub field SF8 so that the pixels f, g, h, i, and j have gray scale values of 128.
Here, when patterns having a gray scale value of 127 and a gray scale value of 128 move at a speed of 6 (pixels and/or frames) to the left, a visual trajectory of a human may be represented as shown in FIG. 1. Here, recognized luminance is represented as shown in FIG. 2B differently from a gray scale value of an original image shown in FIG. 2A. In FIGS. 2A and 2B, the vertical axis denotes a gray scale value, and the horizontal axis denotes a pixel position.
The visual trajectory of the human is positioned in the non-emitting sub fields SF1, SF2, . . . , and SF7 of the pixels f, g, h, i, and j and the non-emitting sub field SF8 of the pixels a, b, c, d, and e so as to allow the human to recognize a gray scale value different from a gray scale value of the original image. This phenomenon mainly appears as a contour form when a pattern having a gently changing gray scale value like a skin tone color moves at a fast speed and is referred to as a false contour. The false contour operates as an important factor degrading a display quality.
As a method of removing such a false contour, there is a method of configuring a plurality of sub fields not to generate non-light-emitting patterns. However, in this method, only gray scale values not having non-light-emitting patterns are used in the plurality of sub fields. Therefore, a gray scale value that may be physically represented in one frame occurs.